Answer
$6-3\sqrt 3$
Work Step by Step
By multiplying both denominator and nominator by $2-\sqrt{3}$, the given expression simplifies to:
$=\dfrac{3}{2+\sqrt{3}} \cdot \dfrac{2-\sqrt{3}}{2-\sqrt{3}}$
$=\dfrac{3(2-\sqrt{3})}{2^2-\sqrt9}$
$=\dfrac{6-3\sqrt{3}}{4-3}$
$=\dfrac{6-3\sqrt{3}}{1}$
$=6-3\sqrt 3$